Conventionally, a precision positioning device converts a torque of a motor to force for moving an object-to-be-positioned via a gear reduction mechanism, a feed screw mechanism, or the like and moves the object-to-be-positioned to a set position by controlling rotation of the motor while feeding back to the motor the current position of the object-to-be-positioned by use of a position sensor or the like. In this case, a mechanism for converting an electric force to a mechanical force for moving the object-to-be-positioned and a feedback control system must have high precision. Such a device becomes very complicated in mechanism, and adjustment and control require considerable skills and time.
There have been proposed various devices which enable precision positioning without use of such a mechanism for converting an electric force to a mechanical force for moving an object-to-be-positioned; i.e., by use of expansion/contraction actuators, such as piezoelectric elements, for converting an electric force directly to a mechanical force for moving an object-to-be-positioned (Patent Documents 1 to 3).    Patent Document 1: Japanese Patent No. 2677625    Patent Document 2: Japanese Patent Application Laid-Open (kokai) No. H6-170762    Patent Document 3: US Patent Application Publication No. 20004/0140737
However, the positioning devices disclosed in Patent Documents 1 and 2 have only one degree of freedom; i.e., along a single axial direction. The positioning device disclosed in Patent Document 3 is designed to position an object-to-be-positioned in a multidimensional space. However, the device is not designed to carry out positioning through elastic deformation of only a single unitary structure, but is designed to carry out positioning through a combination of elastic deformations of a plurality of unitary structures. Thus, the overall structure of the device is very complex.